1. Field of the Invention
One embodiment of the present invention relates to a photodetector including a photodiode, and a display device including a photodiode.
2. Description of the Related Art
Patent Document 1 discloses a liquid crystal display device having an input function using a photosensor. Specifically, the liquid crystal display device includes a switching element and a photoelectric conversion element over a light-transmitting substrate. The thickness of the light-transmitting, substrate is 70 μm to 100 μm. The light-transmitting substrate having such a thickness prevents stray light from a backlight below the light-transmitting substrate from being incident on the photoelectric conversion element. On the other hand, light from an object to be detected which is located over the photoelectric conversion element is incident on the photoelectric conversion element.
[Reference]
    [Patent Document 1] Japanese Published Patent Application No. 2005-10690